The ELMA Fan Module, specifically designed for vertical ventilation of a sub-rack or desktop case, have a pair of variations -- the 160-mm and 220-mm depth modules. These mentioned variations are attached with three fans, which are accordingly arranged in an ideal configuration to thoroughly ensure the cooling of the printed PCBs over the entire width of the rack.
On the other hand, fan modules, with a built-in 84 HP front panels (with on/off switch), are intended for mounting in withdrawble units and desktop cases according to DIN 41494, part 5, being run in and out on card guides.